Press Link to Facebook, Twitter and Google softkey. Sign in to your social sites to get some friends.

From Social screen you can also invite friends by the email address they used to sign in to the B&N site.

From Social Screen you can also set options to share books and to block individual books from prying eyes.

Da nook reads pdf and ePub plus images in jpg, gif, png and bmp.

"Sideload" means transfer files between your puter and da nook. You can sideload backgrounds, screensavers and ebooks you downloads from da web. Dis my favrit sites to find Free ebooks.Update 6/27/2012:
To sideload, connect the nook to your computer with the USB cable. Wait a couple of minutes while it recognizes the device, finds driver, then tells you it connected. Now dat nook looks like a hard drive! Look for a folder named "books," dat where you put pdfs and epubs.

It possible dat Amazon Kindle can read pdf, epub, lit plus mobi, but I can't say cuz I neber seen one. Books for either nook or kindle are encrypted but nook ebooks are supposedly easier to crack because of a weaker encryption algorithm.